fix wide character handling in contents_formatted and contents_diff

4 files changed, 85 insertions, 8 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfb122b..aecda1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 ### Fixed
 
 * Clearing cells now correctly sets the cell background color.
+* Fixed a couple bugs in wide character handling in `contents_formatted` and
+  `contents_diff`.
 
 ## [0.3.1] - 2019-11-06
 
diff --git a/src/row.rs b/src/row.rs
index b563b33..0b834ce 100644
--- a/src/row.rs
+++ b/src/row.rs
@@ -98,8 +98,12 @@ impl Row {
         let mut contents = vec![];
         let mut prev_attrs = attrs;
 
-        let cols = width.min(self.content_width(start));
-        for cell in self.cells().skip(start as usize).take(cols as usize) {
+        let mut cols = 0;
+        for cell in self
+            .cells()
+            .skip(start as usize)
+            .take(width.min(self.content_width(start)) as usize)
+        {
             if prev_was_wide {
                 prev_was_wide = false;
                 continue;
@@ -120,6 +124,7 @@ impl Row {
             });
 
             prev_was_wide = cell.is_wide();
+            cols += if prev_was_wide { 2 } else { 1 };
         }
 
         (contents, prev_attrs, cols)
@@ -132,23 +137,30 @@ impl Row {
         width: u16,
         attrs: crate::attrs::Attrs,
     ) -> (Vec<u8>, crate::attrs::Attrs, u16) {
+        let mut prev_was_wide = false;
         let mut skip = 0;
         let mut contents = vec![];
         let mut prev_attrs = attrs;
-        let mut final_col = 0;
+        let mut cols = 0;
 
-        for (idx, (cell, prev_cell)) in self
+        for (cell, prev_cell) in self
             .cells()
             .zip(prev.cells())
             .skip(start as usize)
             .take(width as usize)
-            .enumerate()
         {
+            if prev_was_wide {
+                prev_was_wide = false;
+                continue;
+            }
+
             if cell == prev_cell {
-                skip += 1;
+                prev_was_wide = cell.is_wide();
+                skip += if prev_was_wide { 2 } else { 1 };
             } else {
                 if skip > 0 {
                     contents.extend(format!("\x1b[{}C", skip).as_bytes());
+                    cols += skip;
                     skip = 0;
                 }
 
@@ -163,11 +175,13 @@ impl Row {
                 } else {
                     b"\x1b[X\x1b[C"
                 });
-                final_col = idx + 1;
+
+                prev_was_wide = cell.is_wide();
+                cols += if prev_was_wide { 2 } else { 1 };
             }
         }
 
-        (contents, prev_attrs, final_col.try_into().unwrap())
+        (contents, prev_attrs, cols)
     }
 
     fn content_width(&self, start: u16) -> u16 {
diff --git a/tests/text.rs b/tests/text.rs
index 24170b8..24c700e 100644
--- a/tests/text.rs
+++ b/tests/text.rs
@@ -46,7 +46,9 @@ fn newlines() {
 #[test]
 fn wide() {
     let mut parser = vt100::Parser::new(24, 80);
+    let screen1 = parser.screen().clone();
     parser.process("aデbネ".as_bytes());
+    let screen2 = parser.screen().clone();
     assert_eq!(parser.screen().cell(0, 0).unwrap().contents(), "a");
     assert_eq!(parser.screen().cell(0, 1).unwrap().contents(), "デ");
     assert_eq!(parser.screen().cell(0, 2).unwrap().contents(), "");
@@ -56,6 +58,27 @@ fn wide() {
     assert_eq!(parser.screen().cell(0, 6).unwrap().contents(), "");
     assert_eq!(parser.screen().cell(1, 0).unwrap().contents(), "");
     assert_eq!(parser.screen().contents(), "aデbネ");
+    assert_eq!(parser.screen().cursor_position(), (0, 6));
+    assert_eq!(
+        parser.screen().contents_formatted(),
+        "\x1b[?25h\x1b[H\x1b[Jaデbネ".as_bytes()
+    );
+    assert_eq!(
+        parser.screen().contents_diff(&screen1),
+        "\x1b[m\x1b[1;1Haデbネ".as_bytes()
+    );
+
+    parser.process(b"\x1b[1;1H\x1b[3Cc");
+    assert_eq!(parser.screen().contents(), "aデcネ");
+    assert_eq!(parser.screen().cursor_position(), (0, 4));
+    assert_eq!(
+        parser.screen().contents_formatted(),
+        "\x1b[?25h\x1b[H\x1b[Jaデcネ\x1b[1;5H".as_bytes()
+    );
+    assert_eq!(
+        parser.screen().contents_diff(&screen2),
+        "\x1b[m\x1b[1;1H\x1b[3Cc".as_bytes()
+    );
 }
 
 #[test]
diff --git a/tests/window_contents.rs b/tests/window_contents.rs
index 9b49421..29b76f8 100644
--- a/tests/window_contents.rs
+++ b/tests/window_contents.rs
@@ -76,6 +76,44 @@ fn empty_cells() {
 }
 
 #[test]
+fn cursor_positioning() {
+    let mut parser = vt100::Parser::new(24, 80);
+    let screen1 = parser.screen().clone();
+
+    parser.process(b":\x1b[K");
+    let screen2 = parser.screen().clone();
+    assert_eq!(parser.screen().cursor_position(), (0, 1));
+    assert_eq!(
+        parser.screen().contents_formatted(),
+        b"\x1b[?25h\x1b[H\x1b[J:"
+    );
+    assert_eq!(parser.screen().contents_diff(&screen1), b"\x1b[m\x1b[1;1H:");
+
+    parser.process(b"a");
+    let screen3 = parser.screen().clone();
+    assert_eq!(parser.screen().cursor_position(), (0, 2));
+    assert_eq!(
+        parser.screen().contents_formatted(),
+        b"\x1b[?25h\x1b[H\x1b[J:a"
+    );
+    assert_eq!(
+        parser.screen().contents_diff(&screen2),
+        b"\x1b[m\x1b[1;1H\x1b[1Ca"
+    );
+
+    parser.process(b"\x1b[1;2H\x1b[K");
+    assert_eq!(parser.screen().cursor_position(), (0, 1));
+    assert_eq!(
+        parser.screen().contents_formatted(),
+        b"\x1b[?25h\x1b[H\x1b[J:"
+    );
+    assert_eq!(
+        parser.screen().contents_diff(&screen3),
+        b"\x1b[m\x1b[1;1H\x1b[1C\x1b[X\x1b[C\x1b[1;2H"
+    );
+}
+
+#[test]
 fn rows() {
     let mut parser = vt100::Parser::new(24, 80);
     let screen1 = parser.screen().clone();